設定prometheus-operator

先決條件

需要一個具有管理員權限的 Kubernetes 集群。

安裝prometheus-operator

安裝prometheus-operator的自定義資源定義 (CRD) 以及運營商本身所需的 RBAC 資源。
運行以下命令以安裝 CRD 並將 Operator 部署到default命名空間中：
LATEST=$(curl -s https://api.github.com/repos/prometheus-operator/prometheus-operator/releases/latest | jq -cr .tag_name)
curl -sL https://github.com/prometheus-operator/prometheus-operator/releases/download/${LATEST}/bundle.yaml | kubectl create -f –
可以使用以下命令檢查是否完成：
kubectl wait –for=condition=Ready pods -l app.kubernetes.io/name=prometheus-operator -n default

佈署範例

這邊是使用OpenShift的yaml去設定相關佈署資訊，更多請見: https://docs.openshift.com/container-platform/4.11/rest_api/monitoring_apis/prometheus-monitoring-coreos-com-v1.html
部署一個簡單的Pod，其中包含 3 個image，用於偵聽端口並公開指標8080

apiVersion: apps/v1
kind: Deployment
metadata:
  name: example-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: example-app
  template:
    metadata:
      labels:
        app: example-app
    spec:
      containers:
      - name: example-app
        image: fabxc/instrumented_app
        ports:
        - name: web
          containerPort: 8080

用一個 Service 對象公開應用程序，該對象選擇所有app標籤具有example-app值的 Pod。Service 對像還指定公開指標的端口。

kind: Service
apiVersion: v1
metadata:
  name: example-app
  labels:
    app: example-app
spec:
  selector:
    app: example-app
  ports:
  - name: web
    port: 8080

最後，我們創建一個 ServiceMonitor 對象，它選擇所有帶有app: example-app標籤的服務對象。ServiceMonitor 對像還有一個team 標籤（在本例中team: frontend為）來標識哪個團隊負責監視應用程序/服務。

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  name: example-app
  labels:
    team: frontend
spec:
  selector:
    matchLabels:
      app: example-app
  endpoints:
  - port: web

部署普羅米修斯

apiVersion: v1
kind: ServiceAccount
metadata:
  name: prometheus

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: prometheus
rules:
- apiGroups: [""]
  resources:
  - nodes
  - nodes/metrics
  - services
  - endpoints
  - pods
  verbs: ["get", "list", "watch"]
- apiGroups: [""]
  resources:
  - configmaps
  verbs: ["get"]
- apiGroups:
  - networking.k8s.io
  resources:
  - ingresses
  verbs: ["get", "list", "watch"]
- nonResourceURLs: ["/metrics"]
  verbs: ["get"]

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: prometheus
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: prometheus
subjects:
- kind: ServiceAccount
  name: prometheus
  namespace: default

更多訊息請見: https://github.com/prometheus-operator/prometheus-operator/blob/main/Documentation/rbac.md
之前，我們已經創建了帶有team: frontend label 的 ServiceMonitor 對象，這裡我們定義 Prometheus 對象應該選擇所有帶有team: frontendlabel 的 ServiceMonitor。這使前端團隊能夠創建新的 ServiceMonitors 和服務，而無需重新配置 Prometheus 對象。

apiVersion: monitoring.coreos.com/v1
kind: Prometheus
metadata:
  name: prometheus
spec:
  serviceAccountName: prometheus
  serviceMonitorSelector:
    matchLabels:
      team: frontend
  resources:
    requests:
      memory: 400Mi
  enableAdminAPI: false

要驗證是否已啟動並正在運行，請運行：

kubectl get -n default prometheus prometheus -w